An Electrical Method for Registration and Analysis of the Movements of the Eyes in Nystagmus

Henriksson, N. G.

doi:10.3109/00016485509118141

Cited by 111 publications

(15 citation statements)

References 12 publications

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“…This is a finding that differs clearly from the ratio generally given in literature of about 70% limited to one side, to 30% bilateral cases. 8. Only in one of our 85 normal subjects we found a spon taneous nystagmus, while Stahle found this disorder only twice in his series of 50 normal subjects.…”

Section: We Divided Our Patients Into 5 Groupsmentioning

confidence: 79%

Clinical Nystagmography

Jongkees¹,

Maas²,

Philipszoon³

1962

ORL

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Section: We Divided Our Patients Into 5 Groupsmentioning

confidence: 79%

Clinical Nystagmography

Jongkees¹,

Maas²,

Philipszoon³

1962

ORL

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“…The middle g rap h is calibrated as seen on the previous ch art. The upper record is a derived nystagm ogram according to Hcnriksson [10]. Only th e slow com ponent of th e nystagm us is recorded and th e " eye speed" traced.…”

Section: Resultsmentioning

confidence: 99%

Recording Vestibular Lateropulsion

Torok¹

1960

Stereotact Funct Neurosurg

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“…The next level of manual methods introduces an analog differentiation of the eye position record to yield an estimate of eye velocity (Henriksson, 1955). Slow phase eye velocity can be manually scored from these records for further analysis.…”

Section: Manual Analysismentioning

confidence: 99%

Spatial orientation in the squirrel monkey: An experimental and theoretical investigation

Merfeld

Young

1993

Ann Biomed Eng

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The interaction of angular and linear stimuli produces a complex alignment of spatial orientation and the vestibulo-ocular reflexes (VOR). This phenomenon was studied by measuring three dimensional eye movements in six male squirrel monkeys during centrifugation in the dark. The axis of centrifuge rotation was always aligned with gravity and with the spinal axis of the upright monkeys. The erect monkeys were placed in one of four orientations: 1) facing into the motion; 2) facing away from the motion; 3) facing the center of rotation; 4) facing away from the center of rotation. These different orientations determined the direction of centripetal acceleration with respect to the monkey. Angular velocity trapezoids were utilized as the motion stimuli with a ramp acceleration (and deceleration) of ten degrees per second squared to a constant velocity of 200 degrees per second. This profile provided a final centripetal acceleration of 1 g, which yielded a gravitoinertial force which was tilted 45 degrees with respect to earth vertical and which had a magnitude of 1.4 g.The orientation of centripetal acceleration dramatically altered the VOR by changing the axis of eye rotation, the peak value of slow phase eye velocity, and the time constant of per-rotary decay. The axis of eye rotation always tended to align with gravito-inertial force, the peak value of slow phase eye velocity was greater when the monkey faced the motion than when it faced away from the motion, and the time constant of decay was smaller when the monkey faced the motion than when it faced away from the motion. These findings were statistically significant (p <0.05) and were very consistent across all monkeys.As previous research has indicated, further modeling of the data indicates that the VOR may be separated into two reflexes: a linear reflex and a rotational reflex. The linear reflex decays as the axis of eye rotation aligns with gravito-inertial force (GIF). These results, along with other data in the literature, indicate that gravito-inertial force is resolved into two components; one representing an internal estimate of linear acceleration and one representing an internal estimate of gravity.A "sensory conflict" model of spatial orientation is developed. The model is based upon observer theory, optimal observer theory (Kalman Filtering), and more general nonlinear concepts. The model hypothesizes that the central nervous system of the squirrel monkey "knows" the dynamics of the sensory organs and uses this knowledge to create an internal model of the sensory systems. The internal model receives as input the internal estimate of linear acceleration and angular velocity. The output of the internal model is the expected sensory afference. The expected sensory afference is compared to the actual sensory afference to yield sensory conflict. The sensory conflict information drives the internal estimate of linear acceleration and angular velocity toward the true values. The predictions of the model are compared to results from this thesis a...

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An Electrical Method for Registration and Analysis of the Movements of the Eyes in Nystagmus

Cited by 111 publications

References 12 publications

Clinical Nystagmography

Clinical Nystagmography

Recording Vestibular Lateropulsion

Spatial orientation in the squirrel monkey: An experimental and theoretical investigation

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